Ionic valve having conducting gaseous paths



Sept. 20, 1938. u. LAMM IONIC VALVE HAVING CONDUCTING GASEOUS PATHS Filed June 5, 1934 JIM e21 for. I 0 201 amm. oer- Patented Sept. 20, i938 PATENT OFFICE rom'o'vAnvs HAVING CONDUCTING GASE- oUs PATHS Uno Lamm, Ludvika, Sweden, assignor to Allmiinna. Svenska Elektriska Aktiebolaget, Vasteras, Sweden, a corporation of Sweden Application June 5, 1934, Serial No. 729,091 In Sweden March 1, 1933 4 Claims.

When an electric current traverses a fluid, either a liquid or an ionized gas, the electrodynamic forces alwaystend to contract the conducting strand or column of fluid. When the said fluid consists of a highly rarefied gas or vapor which is intended to admit the current only in one direction, it is known that this valve action ceases or at least is jeopardized as soon as the gas or vapor pressure rises above a certain value. A strong contractionof the conducting gas or vapor column involves, however, a local increase of pressure which has about the same result as a general increase of pressure, and it is probably this circumstance which has caused that in ionic valves the current per anode can generally not exceed a certain absolute value without causing risk of back-arcing.

The present invention relates to an arrangement for counteracting the contraction of the conducting vapor or gas column in ionic valves which consists in arranging, concentrically with said column, a metallic return conductor for the current passing therethrough, so that the repulsion between the two oppositely directed current causes an expansion of the vapor or gas column. In practice this will hardly be possible otherwise than in such ionic valves which contrary to the usual mercury vapor valves have one cathode for each anode, and then the arrangement involves either that the conductor leading from the oathode. concentrically traverses the anode or that the conductor to the anode concentrically traverses the cathode. The invention is in the first line suited for such ionic valves in which only one pair of electrodes is present in each vessel. The invention further relates to other improvements in valves of the latter kind.

Two forms of the invention are illustrated in vertical sections in Figs. 1 and 2 of the accompanying drawing.

In Fig. 1, the conductor 2 to the anode i is carried through the cathode. The latter consists of a quantity of mercury 3, resting in abowl 4 which is insulated from the rest of the vacuum vessel wall H by a packing 5. The bottom of the bowl is traversed by an insulator bushing 6 for the anode conductor 2 which is further surrounded by an insulatintg tube 1 for instance of quartz. Outside this tube there is a tubular conductor 8 a leading to an anode grid 9, and outside the conductor 8 is another tube H) which may be of quartz and which insulates the conductor thermally as well as electrically from the surrounding arc space. The same function is fulfilled for the upper end of the conductor 2 by the tube 1 which also prevents the formation of an upper footpoint for the arc on the conductor 2. The anode and grid are surrounded by a' sleeve 12.

The active portion of the cathode liquid is limited by a surrounding insulating screen I3 which 5 is continued upwards by a sheet iron screen 14 and together with the latter prevents the immediate contact between the arc and the wall H of the main vessel. 0n the other hand, it is desirable that the rising cathode vapor shall come 10 into contact with said wall in order to condense rapidly. In order to prevent the undesirable formation of a cathode spot on the wall II, the vapor should be substantially deionized when reaching the Wall, and to accomplish this, the sleeve i4 is terminated at its upper end by a grid l5, preferably consisting of plates having a rather large extent in the vertical direction and forming narrow channels between them so as to effect a thorough deionization. The grid may for instance be 20 much denser than an ordinary anode grid, as it is not necessary to pay attention to the passage of a normal arc therethrough. The grid l5 separates the space. enclosed by the said sleeve l2, M from the rest of the vessel, and may also serve the 25 purpose of supporting the anode sleeve 12 in an insulated or uninsulated manner. I6 is an exciting anode projecting through the bottom and surrounded by protecting and insulating tubes I1, I 8.

In the form shown in Fig. 2, the conductor 30 leading from the cathode is carried through the anode. The cathode consists also here of a quantity 23 of liquid metal, as mercury, and is here contained in a bowl 24 of insulating material. The current is led away by a conductor 25 intro- 35 duced from above and terminating in a plate 26 immersed in the metal. The conductor is embraced by a tube 22, for instance of quartz, which protects it against the surrounding arc and insulates it from the surrounding anode 2| and 40 anode conductor 21. The latter is in its turn embraced by a protecting sleeve 28, and all these concentric parts are sealed against each other and the vessel by vacuum tight joints in a customary manner. 29 designates an anode sleeve, 45 30 an exciting anode, and 3| an ignition anode.

I claim as my invention:

1. In high current ionic valves having a conducting gaseous path, a metal vessel, a solid main anode and a liquid cathode therein, and a 50 straight leading-in conductor for one of said electrodes passing through, the other electrode and through the major portion of the arc path between said two electrodes.

2. In high current ionic valves having a con- 55 ducting gaseous path, a metal vessel, a liquid cathode at the bottom thereof, a solid main anode above said cathode, a conductor leading to said anode and passing centrally through said cathode and through the major portion of the are path between said two electrodes, and a tubular insulator separating said conductor from said cathode.

3. In ionic valves having a conducting gaseous path, a metal vessel, a liquid cathode at the bottom thereof, an insulating annular screen surrounding the central portion of said liquid cathode, an anode above said cathode, sleeves surrounding the space between said anode and cathode, and a deionizing grid separating the space enclosed by said sleeves from the rest of the vessel.

4. In ionic valves having a conducting gaseous path, a metal vessel, a liquid cathode at the bottom thereof, an anode arranged centrally above said cathode, a conductor leading to said anode passing centrally through said cathode, two concentrical insulating tubes surrounding said conductor, a grid beneath said anode, a conductor to said grid between said two insulating tubes, and a sleeve surrounding said anode and part of the space between it and the cathode.

UNO IAMM. 

